Appliance latch



NOV 4, 1969 A K. H. ERICKSON 3,476,424

APPLIANCE LATCH Filed March lO, 1967 4 Sheets-Sheet 1 Qdr/ Q'. ric/(Jamc Rvrorasyf Nov. 4, 1969 K. H. ERICKSON APPLIANCE LATCH 4 Sheets-Sheet.2

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Nov. 4, 1969 K. HQ ERICKSON APPLIANCE LATCH 4 Sheets-Sheet 5 Filed MarchlO, 1967 MVSMTOMJ Qian Q4. lrc' c/Qfn,

y Nov. 4,1969 K, H, ER|KS`ON 3,476,424

APPLIANCE LATCH Filed March lO, 1967 4 Sheets-.Ehem 4 w44, y@ ya,cJT-rorzmsxf United States Patent O U.S. Cl. 292--66 8 Claims ABSTRACTOF THE DISCLOSURE A latch for a self-cleaning oven and comprising alever operable to move a bolt first along an angular path intoengagement with a strike on the oven door and then 1nwardly along astraight path to a latched position to draw the door in tightly againstthe oven cabinet. The motion of the lever is transmitted to the bolt bya pivoted driving link which, `with the aid ofl a spring, prevents thebolt from moving inwardly to its latched position unless the door isclosed and the bolt actually engages the strike when the bolt is movedalong the angular path.

BACKGROUND OF THE INVENTION This invention relates to a latch especiallysuitable for use in latching the door of anappliance such as aselfcleaning oven or an automatic dishwasher in a tightly closedcondition prior to operation of the appliance and includes generally anoperating lever for moving a latching bolt lrst along the front of theappliance cabinet from an unlatched position to an extended position toengage a strike on the door, and then inwardly toward the cabinet to alatched position to draw the door tightly closed against the cabinet.More particularly, the invention constitutes an improvement over thelatch disclosed in the copending application of Roland V. Fowler, Ser.No. 592,137, led Nov. 4, 1966, in which the draw-1n motion of the boltis blocked unless the bolt engages the strike and in which engagement ofthe bolt with the strike initiates the draw-in motion thereby to insurethat the bolt cannot be moved inwardly to its latched position when thedoor is open.

SUMMARY OF THE INVENTION The present invention contemplates a new andimproved driving connection between thc operating lever and the bolt ofa latch of the foregoing character to simplify the draw-in motion of thebolt in shifting to the latched position and, at the same time, toreduce wear and promote longer-lasting lubrication between the parts ofthe latch.

BRIEF DESCRIPTION OF THE DRAWING FIGURE 1 is a fragmentary verticalcross-section of an appliance equipped with a latch embodying the novelfeatures of the present invention.

FIG. 2 is a fragmentary Icross-section taken substantially along theline 2-2 of FIG. 1 and showing the parts with the appliance door tightlyclosed and with the bolt in its latched position.

FIG. 3 is a view similar to FIG. 2 and showing the parts with the boltin its unlatched position.

FIG. 4 is a view similar to FIG. 2 and showing the parts with the dooropen and with the bolt in a blocked position.

FIG. 5 is a view similar to FIG. 2 and showing the parts with the doorclosed and with the bolt in its extended position.

FIGS. 6, 7 and 8 are views similar to FIGS. 2, 3 and 4, respectively,with parts being broken away for purposes of clarity.

ICC

FIG. 9 is a fragmentary perspective view of the operating lever and thedriving connection.

DETAILED DESCRIPTION As shown in the drawings for purposes ofillustration, the invention is embodied in a latch mounted within thecabinet 11 of an appliance such as a self-cleaning oven and including anelongated bolt 13 selectively engageable with a strike 14 on the ovendoor 16 to latch the door in a tightly closed position prior tooperation of a hightemperature cleaning unit (not shown) for burning olffood and grease from the oven walls. In such a latch, an ope-ratinglever 17 is pivoted on a latch base or mounting ybracket 19 and isconnected to the bolt in such a manner that counterclockwise swinging ofthe lever from an unlatching position to an intermediate position andthen to a tight-sealing position results in a two-step movement of thebolt to latch the door. As the lever is swung between its successivepositions, the bolt lirst moves along the front of the cabinet from anunlatched position (FIGS. 3 and 7) to an extended position (FIG. 5) inwhich an outer end of the bolt is disposed in engagement with thestrike, and then moves inwardly toward the cabinet to a latched position(FIGS. 2 and 6) to draw the door into tight-sealing relation with thecabinet. To prevent activation of the high-temperature cleaning unitwhen the door is open or free to open, a safety switch 20 (FIG. 2) inthe control circuit of the unit is arranged to be closed to conditionthe circuit for operation only when the lever is in its tight-sealingposition and `when the door is closed and tightly sealed.

In this instance, the latch base 19 is a generally rectangular sheetmetal stamping disposed in a horizontal position between an insulatedtop wall 21 (FIG. 1) of the oven chamber and the upper wall 23 of thecabinet 11. The base is fastened to the top wall 21 by screws 24extending vertically through a pair of laterally spaced mounting wings25 formed near the outer side of the base and a continuous mounting wing26 extending along the inner side of the base. The operating lever 17comprises an elongated handle 27 fastened at its inner end by screws 28to the upper leg 30 (FIG. 9) of a U-shaped plate formed with a lower leg31 which is pivotally connected to the base by an upright pin or rivet33. The handle projects outwardly through an elongated slot 34 (FIG. l)located between the top of the door 16 and the lower side of the cabinetwall 23 and may be provided with a knob (not shown) to facilitategripping of the handle during swinging of the lever about the axis oftherivet.

The bolt 13 also is a sheet metal stamping disposed between the lowerlever leg 31 and the mounting ibase 19 and formed lwith a longitudinalslot 35 (FIG. 6) which loosely receives the rivet 33. A pair of washers36 (FIG. l) on the shank of the rivet holds the upper and lower surfacesof the bolt vertically spaced from the lower lever leg and the mountingbase, respectively. The outer end portion of the bolt projects outwardlythrough a slot 37 (FIG. 6) formed in a flange 39 upturned along theouter edge of the base. lOne side of the outer end portion is notched toform an offset side edge 40 and a hook end 41.

During normal cooking operations when the self-cleaning unit and thelatch are not in use, the lever 17 is disposed in the unlatchingposition (FIGS. 3 and 7), the bolt 13 is disposed in the unlatchedposition, and the hook 41 projects outwardly through a slot 43 formed inthe inner liner of the door 16. In this position of the bolt, the sideedge 40 is spaced laterally from the strike 14 which may be the rightedge of the slot 43 (as viewed from the front of the cabinet) or, asshown herein, the right edge of a slot alined with the slot 43 andformed through a at plate fastened to the inner liner of the door. Tolatch the door and activate the self-cleaning unit, the lever iirst isswung counterclockwise about the rivet 33 to the intermediate position(FIG. 5) to move the bolt to its extended position with the side edge 40in engagement with the strike. The lever then is swung to thetight-sealing position (FIGS. 2 and 6) to draw the bolt inwardly to itslatched position, the hook 41 engaging the strike and drawing the doorti-ghtly against the cabinet 11 as an incident to the inward or draw-inmotion of the bolt.

As shown in FIGS. 2 and 4, the safety switch 20 for the cleaning unit ismounted on the base 19 and includes an operator button 44 which is-depressed to activate the cleaning unit as the lever 17 is moved to itstight-sealing position. In this instance, the button is depresesd by anupright wall 45 (FIGS. 6 and 9) formed integrally with and extendingbetween the upper and lower legs 30 and 31 of the lever. The uprightwall is spaced from the operating button when the lever is in itsunlatching and intermediate positions, and then is moved into engagementwith the button as the lever is moved to its tightsealing position.

Since activation of the high-temperature cleaning unit with the door 1'6in an open position would allow smoke and odors to escape from thecabinet 11 or might cause a sudden ame, the lever 17 is prevented frommoving to its tight-sealing position and against the switch button 44when the door is not closed. As in the latch disclosed in theabove-mentioned application, the bolt 13 and the lever are blocked (seeFIGS. 4 and 8) against movement to their latched and tight-sealingpositions, respectively, when they are moved to their extended andintermediate positions without the bolt engaging the strike 14.Engagement of the bolt with the strike, however, causes the bolt to drawinwardly toward its latched position and, at the same time, frees thelever for move.- ment to its tight-sealing position to depress theswitch button. Accordingly, the latch is strike-responsive since thebolt cannot be moved inwardly until it actually er1- gages the strikeand since enga-gement of the bolt with the strike initiates the draw-inmotion.

In accordance with the present invention, the motion of the operatinglever 17 of a strike-responsive latch of the foregoing character istransmitted to the bolt 13 by an improved pivotal driving connection 46which is subject to less wear and which remains better lubricated underthe high-temperature conditions existing in the oven than the comparableparts of prior latches of the same general type. Moreover, the draw-inmotion undertaken by the bolt in shifting from the extended position tothe latched position is considerably simpler than the motion formerlyrequired in strike-responsive latches.

Generally stated, the driving connection 46 is an L- shaped linkpivotally connected between the bolt 13 and the lever 17 and resilientlyurged in a counterclockwise direction by a spring 47 so as to hold thebolt for movement in an angular path substantially about the axis of therivet 33 from the unlatched position (FIG. 3) to the extended position(FIG. as the lever is swung -from the unlatching position to theintermediate position. When the door 16 is closed, engagement of thebolt with the strike 14 stops further angular movement of the bolt and,upon continued swinging of the lever toward the tight-sealing position(FIG. 2), the link 4'6 shifts the bolt inwardly against the action `ofthe spring and with a simple sliding motion along a substantiallystraight or linear path to the latched position. If the door is open andthe bolt moves to the extended position without enging the strike, thespring-urged link restricts the bolt to movement along the angular pathand prevents the bolt from sliding inwardly to the latched position. Asa result, further swinging of the lever toward the tightsealin-gposition moves the bolt a short distance along the angular path beyondthe extended position and to the position shown in FIGS. 4 and 8 inwhich all motion of both the lever and the bolt is blocked and in whichthe lever is spaced away from the switch button 44 so that theself-cleaning unit cannot be activated.

More specifically, the driving link 46 is located between the upper andlowerlegs 30 and 31 of the lever 17 and is pivotally connected near itsouter end to the upper side of the bolt 13 by a vertically disposedrivet 49 fastened approximately mid-way between the ends of the bolt.Near its inner end, the lever is pivotally connected to the lower leg 31of the lever by a second and parallel rivet 50 fastened to the leg. Themotion of the lever is transmitted to the bolt through the link and thetwo connecting rivets 49 and 50 and, since the link merely pivots on therivets, very little wear occurs at the driving points during the servicelife of thelatch. Moreover, lubricating -grease placed between therive'ts and the link before installation of the latch remains effectiveto -promote free movement of the parts in spite of the high temperatureconditions occurring in the oven.

In this instance, the spring 47 is of the coiled extension type and isstretched between a hook 51 (FIG. 2) projecting inwardly from the baseange 39 and a hook 53 formed integrally with and upstanding from theinner end of the link 46. The spring acts directly on the link to urgethe latter counterclockwise about the rivet 50` and acts through thelink and the rivet 49 to urge the bolt 13 outwardly. The extent to whichthe bolt may move outwardly under the urging of the spring may belimited by engagement of the inner end of the slot 35 in the bolt `withthe rivet 33 or, preferably and as shown herein, such outward movementis limited by engagement of a follower 54 (FIGS. 1 and 8) with a camsurface 55 (FIGS. 2 and 8) on the base 19.

As shown in FIGS. 1, 2 and 8, the cam surface 55 is an outer edge of acurved slot 56 formed through the outer portion of the base 19. Thefollower 54 is formed by a depending pin-like extension formedintegrally with the lower end of the rivet 49 used for connecting thelink 46 to the bolt 13. The follower 54 projects downwardly into theslot 56 from the underside of the bolt and is urged outwardly againstthe outer cam edge 55 due to the action of the spring 47 ur-ging thelink 46 counterclockwise about the rivet 50. In addition to limiting theoutward movement of the bolt, the cam edge 55 guides the bolt from theunlatched position (FIG. 3) to the extended position and determines theshape of the angular path. To accommodate inward movement of thefollower 54 as the bolt slides inwardly to its latched position, theslot 56 is formed with a relatively wide inwardly extending portion 57(see FIGS. 6 and 8) into which the follower moves when the lbolt isdrawn in toward the cabinet.

When the bolt 13 is in its unlatched position and the lever 17 is in itsunlatching position shown in FIG. 3, the spring 47 urges the link 46counterclockwise about the rivet 50 and acts through the link and therivet 49 to urge the bolt outwardly. As a result, the follower 54 ispressed outwardly against the cam edge 55, and the inner end of theelongated slot 35 in the bolt is pressed outwardly against the rivet 33.As the lever is swung counterclockwise toward its intermediate position,its motion is transmitted through the link and to the bolt therebycausing the bolt to move toward its extended position (FIG. 5). Duringthis movement, the follower 54 travels along the cam edge 55 and guidesthe bolt in an angular path substantially about the axis of the rivet33, although in the latch shown the path is not truly arcuate about therivet 33 since the cam edge is shaped to move the bolt inwardly a veryshort distance relative to the rivet 33 as the bolt moves to theextended position.

Upon moving to the extended position with the door 16 closed as shown inFIG. 5, the bolt 13 engages the strike 14 and the latter preventsfurther angular movement of the bolt. The force resulting from continuedswing of the lever 17 toward-the tight-sealing position then overcomesthe force exerted bythe spring 47 and is directed to the bolt throughthe link 46 to slide the bolt inwardly in a straight path to its latchedposition, the follower 54 being pulled away from the cam edge 55 andmoving into the inwardly extendingportion 57 of the slot 56 as anincident to the inward movement of the bolt.

If the door 16 is open so that the bolt 13 fails to engage the strike 14uponbeing moved along the angular path from the unlatched` position(FIG. 3.) to the extended position (FIG. 5,), the force of the spring 47acting through the link 46 keeps the follower 54 pressed` against thecam edge 55 and no force isl present to overcome the spring force and tochange the direction of movement of the bolt. Accordingly, as the lever17 is swung from its intermediate position (FIG. toward itstight-sealing position, the bolt simply continues along the angular pathdefined by the camv edge and moves a short distance beyond the extendedposition (FIG. 5) to the position shown in FIGS. 4 and 8. Upon reachingthe latter position, a lug 60 on the bolt engages a tab 61 projectingupwardly from the base and all further movement of the bolt and thelever thereby is blocked so that the lever cannot be moved all the wayto the tight-sealing position to actuate the switch button 44.

' In'. addition to exerting a force on the bolt 13 preventing the latterfrom sliding inwardly to its latched position when the door 16 is open,the spring 47 automatically returns the lever 17 and the bolt back fromthe blocked positions shown in FIG. 4 as soon as the handle 27 ismanually released by the person operating the latch. When the lever andthe bolt are in their blocked positions, the spring acts through thelink and the rivet 50 to urge the lever clockwise about the rivet 33.Thus, as the handle is released, the spring swings the lever clockwiseback to its unlatching position (FIG. 3). An integral extension 63 onthe lower lever leg 31 moves against a tab 64 upstanding from the base19 to limit the return movement of the leve'r. The clockwise movement ofthe lever is, of course, transmitted to the bolt through the link 46,and thus the bolt also is returned -automatically to its unlatchedposition.

When the door 16 is closed and the bolt 13 engages the strike 14,swinging of the lever 17 fully into its tightsealing position (FIG, 2)causes the rivet 50 to cross over a straight line extending between thehook 51 and the axis of the rivet 33. As a result, the effectivedirection of the spring force is reversed so that the spring 47 urgesthelever counterclockwise about the rivet 33 to hold the lever securelyin the tight-sealing position. It thus is apparent that the link 46 notonly properly directs the spring force to hold the bolt for movement inthe angular path, but also locates the spring force relative to thelever in such a manner that the lever will be returned to the unlatchingposition if the door is open and will be held in the tight-sealingposition when the door is closed.

I claim as my invention:

1. In combination with an appliance cabinet having an access opening, adoor for closing the opening, and a strike on the door for use inlatching the door in a closed position against the cabinet, theimprovement comprising, a latch having a base mounted within thecabinet, an operating lever pivoted on said base for swinging about apredetermined axis between angularly spaced unlatching, intermediate andtight-sealing positions, an elongated bolt, adriving link pivoted nearone end on said bolt and pivoted near its other end on said lever totransmit movement of said lever to said bolt as said lever is swungbetween said positions, a follower on said bolt and spaced from saidaxis, a cam surface on said base engaging said follower and guiding saidbolt for swinging in an angular path from an unlatched position to anextended position tov engage the strike as said lever is swung from saidunlatching position to said intermediate position, means mounting saidbolt for endwise sliding along a straight path intersecting said axisfrom said extended position to a latched position as said bolt engagesthe strike and as said lever is swung to said tight-sealing position,said follower moving with said bolt and shifting away from said camsurface as said bolt slides to said latched position, a spring actingthrough said link and exerting a predetermined force on said bolt forholding said follower against said cam surface when said lever isl swungfrom said unlatching position to said intermediate position and towardsaid tight-sealing .position without said bolt engagng the strikethereby to hold said bolt for swinging in said angular path and torestrict sliding of the bolt along said straight path to said latchedposition, said spring force being overcome upon engagement of said boltwith the strike thereby to permit sliding of the bolt to said latchedposition as said lever is swung to said tight-sealing position.

2. The combination as defined in claim 1 in which said cam surface isthe edge of a slot cut through said base, and said follower is a pincarried by said bolt and projecting into said slot.

3. The combination as deiined in claim 2 in which said slot includes aportion extending inwardly from said cam surface toward said axis, saidfollower pin moving within said inwardly extending portion as said boltslides from said extended position to said latched position.

4. The combination as defined in claim 2 in which said follower pinpivotally mounts said one end of said driving link on said bolt.

5. The combination defined in claim 1 in which a pivot member connectssaid link to said lever., said spring being connected to said link andacting on said lever through said pivot member to urge the lever in onedirection about said axis when the lever is in said intermediateposition and to urge the lever in the opposite direction about said axiswhen the lever is in said tight-sealing position.

6. The combination defined in claim 1 in which said mounting meanscomprisey a longitudinal slot formed through said bolt, and an uprightpin rigid with said base and projecting loosely into said slot, saidupright pin also mounting said lever for swinging between its positions.

7. In combination with an appliance cabinet having an access opening, adoor for closing the opening, and a strike on the door for use inlatching the door in a closed position against the cabinet, theimprovement comprising, a latch having a base mounted within thecabinet, an operating lever pivoted on said base for swinging betweenangularly spaced unlatching, intermediate and tight-sealing positions,an elongated bolt having a longitudinal slot intermediate its ends, apin projecting through said slot and mounting said lever on said basefor swinging between said positions, a driving link pivotally connectednear one end to said bolt and pivotally connected near its other end tosaid lever to transmit movement of said lever to said bolt as said leveris swung between said positions, said link iirst swinging said boltsubstantially about the axis of said pin and in an angular path from anunlatched position to an extended position to engage the strike as saidlever is swung from said unlatching position to said intermediateposition, said link then sliding said bolt endwise along said pin fromsaid extended postion to a latched position directly in response toengagement of the bolt with the strike and as said lever is moved fromsaid intermediate position to said tight-sealing position, and a springon said base urging said bolt and said one end of said link away fromsaid pin with a predetermined force thereby to hold said bolt forswinging along said angular path and to restrict endwise sliding of thebolt until the bolt engages the strike, the spring force being overcomedirectly in response to engagement of the bolt with the strike therebyto permit sliding: of the bolt to said latched position.

8. In combination with an appliance cabinet having an access opening, adoor for closing the opening, and a strike on the door for use inlatching the door in a closed position against the Cabinet, theimprovement comprising, a

latch having a base mounted within the cabinet, an operating leverpivoted on said base for swinging about a predetermined axis betweenangularly spaced unlatchng, intermediate and tight-sealing positions, anelongated bolt connected to said lever, means guiding said bolt rst forswinging in an angular path substantially about said axis from anunlatched position to an extended position to engage the strike as saidlever is swung from said unlatching position to said intermediateposition, and then for endwise sliding relative to said lever in alinear path intersecting said axis from said extended position to alatched position to draw the door inwardly toward the cabinet directlyin response to engagement of the bolt with the strike and as an incidentto swinging of said lever from said intermediate position to saidtight-sealing position, and spring means exerting a predetermined forceon said bolt urging the latter away from said axis thereby to hold thebolt for swinging in said angular path and to restrict sliding of thebolt along said linear path until the bolt engages the strike, thespring force being overcome directly in response to the force created byengagement of the bolt with the strike thereby to permit sliding of thebolt along said linear path to said latched position.

References Cited Fowler 292-66 X DAVID J. WILLIAMOWSKY, Primary ExaminerJ. KARL BELL, Assistant Examiner Us. C1. x.R.

